JP2008105528A - Method of manufacturing sub-frame, and sub-frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sub-frame, without requiring a spacer, when installed in a car body, by freely selecting a material of a collar 90. <P>SOLUTION: This sub-frame has a plurality of frame members 65, a joint member 70 joined to the plurality of frame members 65 and forming a frame-shaped sub-frame, and the collar 90 inserted into a through-hole 80 of the joint member, and is fastened to the car body by a bolt inserted into an installation hole 92 of the collar 90, and is characterized in that the frame member 65 and the joint member 70 are joined by frictional agitating welding, and a diameter ϕC2 of a large diameter part 96 of the collar 90 is formed smaller than a diameter ϕH1' of a small diameter part 85 of the through-hole 80 expanded by a temperature rise caused by the frictional agitating welding. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a subframe manufacturing method and a subframe.

  The vehicle is provided with a pair of left and right side frames constituting a vehicle body skeleton member from the vehicle body front part to the vehicle body rear part. A subframe is connected to the side frame, and various devices of the vehicle are mounted on the subframe. The sub-frame is formed by joining a plurality of frame members by welding or the like.

Recently, a technique for forming a subframe by joining extruded frame members has been proposed.
Japanese Patent Laid-Open No. 2004-133867 discloses a vehicle member coupling in which corresponding end portions of a front side member and a rear side member continuous along the front-rear direction and corresponding end portions of a cross member along the vehicle width direction are coupled by a coupling bracket. The structure is described. Each of these members is formed of an aluminum alloy extruded material having a closed cross-sectional shape. The coupling bracket is formed by cutting an extruded material made of an aluminum alloy having the same cross section in the vertical direction. A square cylindrical frame is formed in the center of the coupling bracket, and a cylindrical nut portion (member fastening portion) is provided inside the frame. The coupling bracket has three pairs of vertical flanges inserted into the corresponding end portions of the members.
JP-A-9-301216

However, in the technique described in Patent Document 1, since the coupling bracket including the nut portion is integrally formed of the extruded material, the nut portion (collar) cannot be configured with a different material harder than the coupling bracket.
Further, since the vertical flange of the coupling bracket is inserted and coupled to the end portion of each member, the end surface of the nut portion is arranged to be recessed from the outer surface of each member. Therefore, it is necessary to arrange a spacer on the end surface of the nut portion when the subframe is fastened to the vehicle body with the bolt inserted into the nut portion.
Accordingly, an object of the present invention is to provide a subframe that can freely select a color material and does not require a spacer when the vehicle body is mounted, and a method for manufacturing the subframe.

  In order to solve the above-described problem, the invention according to claim 1 is a frame-like subframe (for example, the embodiment) formed by joining a plurality of frame members (for example, the frame member 65 in the embodiment) and the plurality of frame members. (For example, the joint member 70 in the embodiment) and a collar (for example, the through-hole (for example, the through-hole 80 in the embodiment)) of the joint member or the frame member. A collar 90) according to an embodiment, and a method of manufacturing a subframe fastened to a vehicle body by a bolt inserted into the collar, wherein the frame member and the joint member are joined by friction stir welding, and the friction The collar is inserted into the through-hole enlarged due to the temperature rise accompanying stir welding. To.

  The invention according to claim 2 includes a plurality of frame members, a joint member joined to the plurality of frame members to form a frame-shaped subframe, and a collar inserted into the joint member or the through hole of the frame member, The frame member and the joint member are joined by friction stir welding, and the diameter of the collar is a temperature associated with the friction stir welding. It is characterized in that it is formed smaller than the diameter of the through-hole enlarged by rising.

  The invention according to claim 3 is characterized in that a flange portion (for example, the flange portion 94 in the embodiment) is formed at one end portion in the axial direction of the collar.

  According to the first aspect of the invention, since the collar is inserted into the through-hole enlarged due to the temperature rise accompanying friction stir welding, the collar can be easily and reliably inserted. Further, since the collar is fixed by reducing the through-hole due to the temperature drop after welding, the collar can be fixed easily and reliably. As described above, since the collar can be inserted and fixed easily and reliably, it is possible to adopt a collar separate from the joint member or the frame member, and the color material can be freely selected. it can.

  According to the second aspect of the invention, the diameter of the collar is smaller than the diameter of the through-hole enlarged due to the temperature rise accompanying friction stir welding, so that the through-hole enlarged due to the temperature rise accompanying friction stir welding is used. It becomes possible to insert a color. Therefore, it is possible to employ a color separate from the joint member or the frame member, and the color material can be freely selected.

  According to the invention which concerns on Claim 3, it becomes possible to make a flange part function as a spacer by setting the thickness and area of a flange part suitably, and inserting a color | collar in a through-hole. Therefore, no spacer is required when the subframe is mounted on the vehicle body.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a case where a subframe according to the present invention is applied to a subframe on which a fuel cell is mounted in a fuel cell vehicle will be described as an example.
(First embodiment)
FIG. 1 is an explanatory view of a side surface of a vehicle, and FIG. 2 is a cross-sectional view taken along line AA of FIG. As shown in FIGS. 1 and 2, a fuel cell vehicle has a fuel cell stack 12 that generates electricity by an electrochemical reaction between hydrogen and oxygen, and is mounted under the floor of a vehicle body. Drives by driving the drive motor. The fuel cell stack 12 is a well-known polymer electrolyte fuel cell (PEMFC) in which a number of unit cells (unit fuel cells) are stacked, for example, and supplies hydrogen gas as a fuel gas to the anode side, and the cathode side By supplying air containing oxygen as an oxidant gas, electric power is generated by an electrochemical reaction and water is generated.

  As shown in FIG. 1, the fuel cell vehicle is provided with a pair of left and right side frames 2 that form a vehicle body skeleton member below the floor panel 1 from the vehicle body front portion to the vehicle body rear portion. As shown in FIG. 2, a side sill 5 is joined to the outer walls 3 of the left and right side frames 2 via an outrigger 4. A cross member (not shown) which is a vehicle body skeleton member is connected to the side frame 2 in the vehicle width direction.

As shown in FIG. 1, a front sub-frame 11 is attached to the motor room 10 at the front of the vehicle body from the lower side with respect to the side frame 2. The front subframe 11 is equipped with a compressor 13 for supplying air to the fuel cell stack 12, a pump motor unit 15 including a driving motor 14 for traveling, and the like.
A rear sub-frame 16 is attached to the rear portion of the vehicle body from the lower side with respect to the side frame 2. In addition to the wheels and suspension, the rear subframe 16 is mounted with a hydrogen tank 17 and a storage battery 18 that store hydrogen as fuel of the fuel cell stack 12.

On the side frame 2, the floor panel 1 is joined. The front end portion of the floor panel 1 rises to the front and continues to the dash lower 1a, and the rear end portion of the floor panel 1 extends to a position covering the upper portion of the hydrogen tank 17 of the rear subframe 16.
The floor panel 1 is formed with a floor tunnel 22 that bulges upward between the left and right front seats 20 and rear seats 21 from the lower end of the dash lower 1a toward the rear of the vehicle body. The floor tunnel 22 bulges further upward between the left and right front seats 20 and 20 to form a center console 23.

  As shown in FIG. 2, a reinforcement 26 that forms a triangular cross section is joined to a lower surface portion from the left and right rising portions 24 of the floor tunnel 22 to the side wall 25 of the center console 23. The console 23 is reinforced. A center frame 27 having a closed cross-sectional structure is joined to the lower surface of the reinforcement 26 along the longitudinal direction of the vehicle body. A reinforcing frame 28 having a closed cross-sectional structure is joined to the corner portion between the inner wall of the side frame 2 and the floor panel 1 along the longitudinal direction of the vehicle body.

  Subframes 40 are attached to the lower surfaces of the center frame 27 and the reinforcing frame 28. As shown in FIG. 1, the fuel cell stack 12 and its accessories 19 are mounted on the subframe 40. The fuel cell 12 and the accessories 19 are disposed in the center console 23, that is, below the floor panel 1 that is outside the passenger compartment. Accordingly, the fuel cell is isolated from the passenger's living space by the floor panel 1 (center console 23).

(Sub-frame)
FIG. 3 is a perspective view of the subframe. The sub frame 40 includes a pair of sub center frames 44, 44 extending in the vehicle front-rear direction. The sub-center frames 44 and 44 are connected to the lower side of the center frame described above. The pair of sub-center frames 44, 44 are connected by a front sub-cross frame 41 and a rear sub-cross frame 42 arranged in the vehicle width direction. Thereby, the sub-frame 40 is comprised by the frame shape frame | skeleton. The rear end portions of the sub-center frames 44, 44 extending rearward from the rear sub-cross frame 42 are connected by an end frame 45 disposed in the vehicle width direction.
Intermediate frames 47, 47 extend from the sub center frames 44, 44 toward the outside in the vehicle width direction between the front and rear sub cross frames 41, 42. The front ends of the intermediate frames 47 and 47 are connected to the lower side of the reinforcing frame described above.

Various frames constituting the sub-frame 40 are constituted by a frame member 65 and a joint member 70 disposed at an intersection of the plurality of frame members 65. Hereinafter, the frame member 65 and the joint member 70 in the P part will be described as an example, but the other parts are configured in the same manner.
FIG. 4 is an enlarged exploded view of a portion P in FIG. As shown in FIG. 4, the frame member 65 is formed in a rectangular closed cross-sectional structure by extruding a metal material such as aluminum. The frame member 65 has a hollow structure having an opening 66 at the end.

  The joint member 70 is formed into a solid structure using a metal material such as a magnesium alloy. The joint member 70 includes a rectangular parallelepiped main body 71. On the side surface of the main body 71, a fitting portion 76 that fits into the opening 66 of the frame member 65 is formed to protrude. And the fitting part 76 of the joint member 70 is inserted in the opening 66 of the frame member 65, and the sub-frame is assembled. Further, a fitting portion 69 between the fitting portion 76 of the joint member 70 and the frame member 65 is joined by friction stir welding (hereinafter referred to as “FSW”).

The FSW will be described with reference to FIG. For the FSW, a cylindrical stirring rod 100 having a protrusion 101 at the center is used. Then, the stirring rod 100 is rotated around the central axis while pressing the stirring rod 100 toward the fitting portion 69 between the fitting portion 76 of the joint member 70 and the frame member 65. As a result, frictional heat is applied to the fitting portion 69 to create a plasticized / viscous layer on the material. When the stirring rod 100 is advanced along the fitting portion 69, the fitting portion 69 is sequentially plasticized. When the plasticized material is solidified, the FSW joint 110 is formed in the fitting portion 69.
In addition, as shown by the broken line 110 in FIG. 3, the frame member and the joint member that constitute the subframe are joined by FSW.

(Color)
Returning to FIG. 4, a through hole (not shown) is formed through the body 71 of the joint member 70 in the vertical direction, and a collar 90 is inserted into the through hole. A mounting hole 92 is formed along the central axis of the collar 90. By passing bolts from below into the mounting holes 92, the subframe 40 is fastened to the center frame 27 and the reinforcing frame 28 as shown in FIG.

  FIG. 5A is a cross-sectional view of the collar according to the first embodiment. The collar 90 is integrally formed in a cylindrical shape with a metal material such as aluminum that is harder (higher buckling strength) than the joint member. Convex portions and / or concave portions are formed on the outer peripheral surface of the collar 90. Specifically, a large-diameter portion 96 having a diameter of φC2 is formed in the central portion in the axial direction of the collar 90, and small-diameter portions 95 and 97 having a diameter of φC1 (<C2) are formed in the vicinity of both end portions in the axial direction of the collar 90. ing. Thus, the small diameter portion 95, the large diameter portion 96, and the small diameter portion 95 are sequentially arranged along the axial direction of the collar 90, and a convex portion having the large diameter portion 96 at the top is formed on the outer peripheral surface of the collar 90. Further, a flange portion 94 having a diameter φC0 (> C1) is formed on the outer side in the axial direction of one small diameter portion 95. As a result, the large diameter portion 96, one small diameter portion 95 and the flange portion 94 are sequentially arranged along the axial direction of the collar 90, and a concave portion having the one small diameter portion 95 as a bottom is formed on the outer peripheral surface of the collar 90. Yes.

  FIG. 5B is a cross-sectional view of a collar according to a modification of the first embodiment. In this modification, a large diameter portion 96 having a diameter of φC2 is formed at one end portion in the axial direction of the collar 91, and a small diameter portion 95 having a diameter of φC1 (<C2) is formed in the vicinity of the other end portion. A flange portion 94 having a diameter φC0 (> C1) is formed outside the small-diameter portion 95. Also in this modified example, the large diameter portion 96, the small diameter portion 95, and the flange portion 94 are sequentially arranged along the axial direction of the collar 90, and a recess having the small diameter portion 95 as a bottom portion is formed on the outer peripheral surface of the collar 90.

  6 is a cross-sectional view taken along line BB in FIG. As shown in FIG. 6A, the joint member 70 is formed with a through hole 80 for inserting the collar according to the first embodiment in the vertical direction. Concave portions and / or convex portions are formed on the inner peripheral surface of the through hole 80 corresponding to the convex portions and / or concave portions formed on the outer peripheral surface of the collar. Specifically, a large-diameter portion 86 having a diameter of φH2 (≈C2) is formed at the axially central portion of the through hole 80, and a small-diameter portion 85 having a diameter of φH1 (≈C1) at both axial ends of the through-hole 80. Is formed. Thereby, the small diameter portion 85, the large diameter portion 86, and the small diameter portion 85 are sequentially arranged along the axial direction of the through hole 80, and a recess having the large diameter portion 86 as a bottom is formed on the inner peripheral surface of the through hole 80. Yes.

By the way, as shown in FIG.6 (b), if FSW is implemented in the fitting part 69 of the joint member 70 and the frame member 65, the temperature of the joint member 70 will rise. Thereby, the joint member 70 is thermally expanded, and the diameter φH1 of the small diameter portion 85 of the through hole 80 is enlarged. For example, the diameter φH1 of the small diameter portion 85 of the through hole 80 at room temperature is 36 mm, the linear expansion coefficient α of the magnesium alloy constituting the joint member 70 is 2.7 × 10 ⁻⁵ / ° C., and the temperature change ΔT of the joint member 70 is Assuming that the temperature is 180 ° C. (200 ° C.-20 ° C.), the diameter φH1 ′ of the small diameter portion of the through hole 80 after the temperature rise is expressed by the following equation.
H1 ′ = H1 + H1 · α · ΔT = 36.175

  Therefore, in this embodiment, the diameter φC2 of the large diameter portion 96 of the collar 90 is set smaller than the diameter φH1 ′ of the small diameter portion 85 of the through hole 80 after the temperature rises. In addition, the diameter φC2 of the large diameter portion 96 of the collar 90 is set larger than the diameter φH1 of the small diameter portion 85 of the through hole 80 at room temperature. For example, when the diameter φH1 of the small diameter portion 85 of the through hole 80 at room temperature is 36 mm and the diameter φH1 ′ of the small diameter portion 85 of the through hole 80 after the temperature rise is 36.175 mm, the large diameter portion of the collar 90 The diameter φC2 of 96 may be set to about 36.170 mm.

(Subframe manufacturing method)
Next, a method for manufacturing a subframe according to the present embodiment will be described with reference to FIG. FIG. 6 is a process diagram of the method for manufacturing a subframe according to the first embodiment, and is a cross-sectional view taken along line BB of FIG.
First, as shown in FIG. 6A, the fitting portion 76 of the joint member 70 is inserted into the frame member 65.
Next, as shown in FIG. 6B, FSW is performed on the fitting portion 69 between the joint member 70 and the frame member 65. The temperature of the weld during the FSW is increased to about 400 to 500 ° C. The temperature at a position 50 mm away from the tip of the stirring rod 100 rises to about 50 to 100 ° C. Therefore, the temperature around the through hole 80 in the joint member 70 increases from room temperature (about 20 ° C.) to about 200 ° C. As a result, the diameter of the small diameter portion 85 of the through hole 80 increases from φH1 to φH1 ′.

  In the present embodiment, the diameter φC2 of the large diameter portion 96 of the collar 90 is set smaller than the diameter φH1 ′ of the small diameter portion 85 of the through hole 80 after the temperature rises. Therefore, after the temperature of the joint member 70 rises, even the large diameter portion 96 of the collar 90 can pass through the small diameter portion 85 of the through hole 80. Therefore, the collar 90 is inserted into the through hole 80 after the temperature of the joint member 70 has sufficiently increased due to the implementation of FSW. Note that the collar 90 before insertion is preferably kept at room temperature or cooled.

As shown in FIG. 6C, the collar 90 is inserted into the through hole 80, and the lower surface of the flange portion 94 of the collar 90 is brought into contact with the upper surface of the joint member 70.
After the collar 90 is inserted, the joint member 70 is cooled to room temperature. In the present embodiment, the diameter φC2 of the large diameter portion 96 of the collar 90 is set larger than the diameter φH1 of the small diameter portion 85 of the through hole 80 at room temperature. Therefore, the large diameter portion 96 of the collar 90 cannot pass through the small diameter portion 85 of the through hole 80 at room temperature. Further, since a convex portion having the large-diameter portion 96 as a top portion is formed on the outer peripheral surface of the collar 90 and a corresponding concave portion is formed on the inner peripheral surface of the through hole 80, the collar 90 is disposed on both sides in the axial direction. Can be prevented from falling out.

  As described above, according to the present embodiment, since the collar 90 is inserted into the through-hole 80 expanded due to the temperature rise accompanying the FSW, the collar can be easily and reliably inserted without providing a press-fitting process or the like. It becomes possible. Further, since the through hole 80 is reduced and the collar 90 is fixed due to the temperature drop after welding, the collar can be easily and reliably fixed without providing a separate welding process or the like. For example, when the aluminum collar 90 is fixed to the magnesium alloy joint member 70, normal TIG welding or the like cannot be used, but according to the present embodiment, welding using electricity or gas is required. The collar 90 can be fixed to the joint member 70 without doing so.

  As described above, since the collar can be inserted and fixed easily and reliably, it is possible to employ a collar 90 that is separate from the joint member 70. Therefore, the material of the collar 90 can be freely selected. For example, if a material harder than the constituent material of the joint member 70 (high buckling strength) is selected as the constituent material of the collar 90, loosening of bolts and the like inserted into the mounting holes 92 of the collar 90 can be prevented.

  Further, according to the present embodiment, since the heat associated with the FSW is used, it is not necessary to separately heat the joint member 70 for inserting the collar 90, and an increase in manufacturing cost can be suppressed. In addition, since the joint member 70 is heated separately, it is not necessary to blow with a flame, and the collar 90 can be inserted even if there is no experience. In addition, since heat is stably generated when the FSW is performed, once the work conditions (time from the start of the FSW to the insertion of the collar, rotation speed of the stirring rod, moving speed, etc.) are set, stable insertion work is possible. . Further, the dimensions of the collar 90 and the through hole 80 can be estimated by using the temperature change amount of the joint member 70 by FSW and the linear expansion coefficient of the constituent material.

  In the present embodiment, the flange portion 94 is formed at one end portion of the collar 90 in the axial direction. By setting the thickness and area of the flange portion 94 as appropriate and inserting the collar 90 into the through hole 80, the flange portion 94 can function as a spacer. Therefore, no spacer is required when the subframe is mounted on the vehicle body.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a process diagram of the method for manufacturing a subframe according to the second embodiment, and is a cross-sectional view at a position corresponding to the line BB in FIG. 4. In the first embodiment, the collar is inserted into the through hole of the joint member having the solid structure. However, in the second embodiment shown in FIG. 7, the collar 93 is inserted into the through hole 80 of the frame member 65 having the hollow structure. Is different. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

  As shown in FIG. 7A, the frame member 65 is formed in a hollow structure with a closed cross section. Through holes 80 and 80 are formed in a pair of wall surfaces facing each other in the vertical direction among the wall surfaces constituting the frame member 65. The through holes 80 are formed with substantially the same diameter φH1 at substantially the same position in plan view.

  As shown in FIG. 7B, the collar 93 is integrally formed in a cylindrical shape with a metal material such as aluminum. A large-diameter portion 96 having a diameter of φC2 is formed in the central portion of the collar 93 in the axial direction. The width of the large diameter portion 96 in the axial direction is formed to be equal to the distance between the pair of wall surfaces in which the through holes 80 and 80 are formed in the frame member 65. Small diameter portions 95 having a diameter of φC1 (≈H1 <C2) are formed on both outer sides in the axial direction of the large diameter portion 96. The width of the small diameter portion 95 in the axial direction is formed to be equal to the thickness of the wall surface of the frame member 65 where the through holes 80 and 80 are formed. A flange portion 94 having a diameter φC0 (> C1) is formed on the outer side in the axial direction of one small diameter portion 95 disposed above the collar 93. A large-diameter portion 96 having a diameter of φC2 is formed on the outer side in the axial direction of the other small-diameter portion 95 disposed below the collar 93.

By the way, when FSW is performed on the fitting portion 69 between the joint member 70 and the frame member 65, the temperature of the frame member 65 as well as the joint member 70 rises. Thereby, the frame member 65 is thermally expanded, and the diameter φH1 of the through hole 80 is enlarged. For example, the diameter φH1 of the through-hole 80 at room temperature is 20 mm, the linear expansion coefficient α of aluminum constituting the frame member 65 is 2.3 × 10 ⁻⁵ / ° C., and the temperature change ΔT of the frame member 65 is 75 ° C. (100 ° C. (−25 ° C.), the diameter φH1 ′ of the through hole 80 after the temperature rise is expressed by the following equation.
H1 ′ = H1 + H1 · α · ΔT = 20.035

  Therefore, in this embodiment, the diameter φC2 of the large diameter portion 96 of the collar 93 is set smaller than the diameter φH1 ′ of the through hole 80 after the temperature rises. Moreover, the diameter φC2 of the large diameter portion 96 of the collar 93 is set larger than the diameter φH1 of the through hole 80 at room temperature. For example, when the diameter φH1 of the through hole 80 at room temperature is 20 mm and the diameter φH1 ′ of the through hole 80 after the temperature rise is 20.0.035 mm, the diameter φC2 of the large diameter portion 96 of the collar 93 is 20.030 mm. What is necessary is just to set to a grade.

(Subframe manufacturing method)
Next, a method for manufacturing a subframe according to the present embodiment will be described with reference to FIG. FIG. 7 is a process diagram of the manufacturing method of the subframe according to the first embodiment, and is a cross-sectional view taken along line BB of FIG.
First, as shown in FIG. 7A, the fitting portion 76 of the joint member 70 is inserted into the frame member 65.

Next, as shown in FIG. 7B, FSW is performed on the fitting portion 69 between the joint member 70 and the frame member 65. Thereby, the temperature around the through hole 80 in the frame member 65 rises from room temperature (about 25 ° C.) to about 100 ° C. Thereby, the diameter of the through-hole 80 is expanded from φH1 to φH1 ′.
In the present embodiment, the diameter φC2 of the large diameter portion 96 of the collar 93 is set smaller than the diameter φH1 ′ of the through hole 80 after the temperature rises. Therefore, the collar 93 is inserted into the through hole 80 after the temperature of the frame member 65 has sufficiently increased due to the implementation of FSW.

As shown in FIG. 7C, the collar 93 is inserted into the through hole 80, and the lower surface of the flange portion 94 of the collar 93 is brought into contact with the upper surface of the frame member 65.
When the frame member 65 is cooled to room temperature after the collar 93 is inserted, the diameters of the through holes 80 and 80 are reduced from φH1 ′ to φH1. Accordingly, the through holes 80 and 80 of the frame member 65 are fitted into the small diameter portions 95 and 95 of the collar 93. Further, the large diameter portion 96 of the collar 93 is disposed between a pair of wall surfaces in the frame member 65 where the through holes 80 are formed. In the present embodiment, the diameter φC2 of the large diameter portion 96 of the collar 93 is set larger than the diameter φH1 of the through hole 80 at room temperature. Therefore, the large diameter portion 96 of the collar 93 cannot pass through the through hole 80 at room temperature. Therefore, it is possible to prevent the collar 93 from slipping out on both sides in the axial direction.

Also in the second embodiment described above, the same operational effects as those in the first embodiment can be obtained. That is, the insertion and fixing of the collar 93 with respect to the frame member 65 can be performed easily and reliably. Therefore, the constituent material of the collar 93 can be freely selected.
Further, by mounting the collar 93 on the frame member 65 having a hollow structure, the vehicle body attachment portion can be disposed on the frame member 65.

The present invention is not limited to the embodiment described above.
For example, in the embodiment, the sub-frame in which the fuel cell is mounted at the center of the vehicle has been described as an example. However, the present invention can be applied to a sub-frame in which devices other than the fuel cell are mounted in the front or rear of the vehicle. In addition, the shape of the subframe is not limited to the shape of the above embodiment, and can be changed as appropriate.

It is explanatory drawing of a vehicle side surface. It is sectional drawing in the AA of FIG. It is a perspective view of a subframe. It is an expansion exploded view of the P section of FIG. (A) is sectional drawing of the color which concerns on 1st Embodiment, (b) is sectional drawing of the color which concerns on the modification of 1st Embodiment. It is process drawing of the manufacturing method of the sub-frame which concerns on 1st Embodiment, and is sectional drawing in the BB line of FIG. It is process drawing of the manufacturing method of the sub-frame which concerns on 2nd Embodiment, and is sectional drawing in the part corresponded to the BB line of FIG.

Explanation of symbols

  40 ... subframe 65 ... frame member 70 ... joint member 80 ... through hole 85 ... small diameter portion 90 ... collar 94 ... flange portion 96 ... large diameter portion

Claims (3)

A plurality of frame members; a joint member that joins the plurality of frame members to form a frame-shaped subframe; and a collar that is inserted into a through hole of the joint member or the frame member. A method of manufacturing a subframe that is fastened to a vehicle body by a bolt,
Joining the frame member and the joint member by friction stir welding,
A method of manufacturing a sub-frame, wherein the collar is inserted into the through-hole enlarged due to a temperature rise accompanying the friction stir welding. A plurality of frame members; a joint member joined to the plurality of frame members to form a frame-like subframe; and a collar inserted into a through hole of the joint member or the frame member, and inserted into the collar A subframe fastened to the vehicle body by bolts,
The frame member and the joint member are joined by friction stir welding,
The diameter of the said collar is formed smaller than the diameter of the said through-hole expanded by the temperature rise accompanying the said friction stir welding.   The subframe according to claim 2, wherein a flange portion is formed at one end of the collar in the axial direction.

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